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The increased water scarcity, depletion of freshwater resources, and rising environmental awareness are stressing for the development of sustainable wastewater treatment processes. Microalgae-based wastewater treatment has resulted in a paradigm shift in our approach toward nutrient removal and simultaneous resource recovery from wastewater. Wastewater treatment and the generation of biofuels and bioproducts from microalgae can be coupled to promote the circular economy synergistically. A microalgal biorefinery transforms microalgal biomass into biofuels, bioactive chemicals, and biomaterials. The large-scale cultivation of microalgae is essential for the commercialization and industrialization of microalgae biorefinery. However, the inherent complexity of microalgal cultivation parameters regarding physiological and illumination parameters renders it challenging to facilitate a smooth and cost-effective operation. Artificial intelligence (AI)/machine learning algorithms (MLA) offer innovative strategies for assessing, predicting, and regulating uncertainties in algal wastewater treatment and biorefinery. The current study presents a critical review of the most promising AI/MLAs that demonstrate a potential to be applied in microalgal technologies. The most commonly used MLAs include artificial neural networks, support vector machine, genetic algorithms, decision tree, and random forest algorithms. Recent developments in AI have made it possible to combine cutting-edge techniques from AI research fields with microalgae for accurate analysis of large datasets. MLAs have been extensively studied for their potential in microalgae detection and classification. However, the ML application in microalgal industries, such as optimizing microalgae cultivation for increased biomass productivity, is still in its infancy. Incorporating smart AI/ML-enabled Internet of Things (IoT) based technologies can help the microalgal industries to operate effectively with minimum resources. Future research directions are also highlighted, and some of the challenges and perspectives of AI/ML are outlined. As the world is entering the digitalized industrial era, this review provides an insightful discussion about intelligent microalgal wastewater treatment and biorefinery for researchers in the field of microalgae., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Photosynthetic microbial fuel cells (pMFC) represent a promising approach for treating methanol (CH 3 OH) wastewater. However, their use is constrained by a lack of knowledge on the extracellular electron transfer capabilities of photosynthetic methylotrophs, especially when coupled with metal electrodes. This study assessed the CH 3 OH oxidation capabilities of Rhodobacter sphaeroides 2.4.1 in two-compartment pMFCs. A 3D nickel (Ni) foam modified with plasma-grown graphene (Gr) was used as an anode, nitrate mineral salts media (NMS) supplemented with 0.1% CH 3 OH as anolyte, carbon brush as cathode, and 50 mM ferricyanide as catholyte. Two simultaneous pMFCs that used bare Ni foam and carbon felt served as controls. The Ni/Gr electrode registered a two-fold lower charge transfer resistance (0.005 kΩ cm 2 ) and correspondingly 16-fold higher power density (141 mW/m 2 ) compared to controls. The underlying reasons for the enhanced performance of R. sphaeroides at the graphene interface were discerned. The real-time polymerase chain reaction (PCR) analysis revealed the upregulation of cytochrome c oxidase, aa3 type, subunit I gene, and Flp pilus assembly protein genes in the sessile cells compared to their planktonic counterparts. The key EET pathways used for sustaining CH 3 OH oxidation were discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Experimental data from fixed-bed column studies and a numerical model based on convection-dispersion equations were used to describe transport and retention of Graphene Oxide (GO) in sand, biochar (BC), and BC modified with nanoscale zero-valent iron (BC-nZVI). Three blocking functions, namely no blocking, site-blocking, and depth-dependent blocking, were used to analyze GO transport and retention behavior in each media as a function of Ionic Strength (IS). An inverse modeling approach was implemented to determine the attachment coefficient (K a ) and maximum solid-phase retention capacity (S max ). The Langmuirian attachment model with site-blocking function effectively described experimental GO breakthrough curves (R 2  ~ 0.70-0.99) compared to other models, indicating the importance of introducing a limit on the attachment capacity of the media. The K a values for BC and BC-nZVI were significantly higher than sand, attributable to high porosity, roughness, and surface chemical properties. The models predicted an increasing trend in K a (0.065 to 0.615 min -1 ) in BC with increasing IS (0.1 to 10 mM), while K a values decreased (2.26 to 0.349 min -1 ) for BC-nZVI. A consistent increase in S max was observed for both BC and BC-nZVI with increasing IS. Scenario analysis was conducted to further understand the effect of influent IS, GO concentration, and treatment depth. BC-nZVI exhibited a higher K a and S max and as a result, higher GO retention than BC at lower IS (0.1 and 1.0 mM). BC-nZVI had a relatively lower K a (0.349 min -1 ) at 10 mM IS, however, it outperformed BC when GO retention capacities are compared over a longer period attributable to a higher S max (6.47). Complete GO breakthrough occurred in a 5 cm media after 350 and 465 days for BC and BC-nZVI, respectively at 10 mM IS and influent concentration of 0.1 mg·L -1 . GO breakthrough time increased with increasing treatment depth, however, the relation was non-linear., (Published by Elsevier B.V.)

The increasing use of engineered nanoparticles (ENPs) in consumer products has led to their increased presence in natural water systems. Here, we present a critical overview of the studies that analyzed the fate and transport behavior of ENPs using real environmental samples. We focused on cerium dioxide, titanium dioxide, silver, carbon nanotubes, and zinc oxide, the widely used ENPs in consumer products. Under field scale settings, the transformation rates of ENPs and subsequently their physicochemical properties (e.g., toxicity and bioavailability) are primarily influenced by the modes of interactions among ENPs and natural organic matter. Other typical parameters include factors related to water chemistry, hydrodynamics, and surface and electronic properties of ENPs. Overall, future nanomanufacturing processes should fully consider the health, safety, and environmental impacts without compromising the functionality of consumer products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Methanol solvents that are used in hydraulic fracturing often return back to the surface in the form of recalcitrant flowback water. Here, the indigenous methylotrophic bacteria from flowback water were enriched and used to generate electricity from methanol in a two-compartment microbial fuel cell (CH 3 OH-MFC). An identical MFC based on a tryptone-yeast extract (TY-MFC) was used as a control. CH 3 OH-MFC yielded a 2.7-fold thicker biofilm dominated by electrogenic species (81%) and higher power density (76 mW/m 2 ) compared with TY-MFC (50 mW/m 2 ). Illumina MiSeq sequencing of the 16S rRNA gene in TY-MFC revealed classes from Actinobacteria, Bacteroidia and γ-proteobacteria. The CH 3 OH-MFC yielded α-proteobacteria, β-proteobacteria, γ-proteobacteria and Bacteroidia, with a dominant fraction of Rhodobacter sphaeroides (~29%). We discuss the potential pathways used by R. sphaeroides to maintain syntrophic cooperation with other bacterial and archaeal members to sustain CH 3 OH oxidation. Finally, we establish that a pure culture of R. sphaeroides 2.4.1 generates electricity directly from methanol., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This study evaluates and compares the performance of microbial fuel cells (MFCs) and microbial capacitive deionization cells (MCDCs) fed with wastewater produced from the Bakken shale. The produced water was characterized by high levels of dissolved solids and chemical oxygen demand (COD). Two-compartment MFCs and three-compartment MCDCs were evaluated under batch-fed mode using mixed microbial consortia in the anode, ferricyanide in the cathode, and produced water as the electrolyte in the anode and capacitive deionization units. COD removal in the MFCs was 88%, while that in the MCDCs was limited to 76%. The lower performance of the MCDCs was due to the large impedance (6600 Ω cm 2 ) compared with the MFCs (870 Ω cm 2 ). However, the MCDCs achieved two-fold higher removal of dissolved solids. Both the MFCs and MCDCs suffered from a higher impedance induced by fouling in the latter stages of the operation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The United States faces a significant burden in treating 0.61billionkg of defective tomatoes (culls) every year. We present a proof-of-concept for generating electricity from culled tomatoes in microbial-electrochemical systems (MESs). This study delineates impedance behavior of the culled tomatoes in MESs and compares its impedance spectra with that of soluble substrates (dextrose, acetate, and wastewater). A series of AC and DC diagnostic tests have revealed the superior performance of the culled tomatoes compared to the pure substrates. Cyclic voltammetry results have indicated the active role of indigenous, diffusible redox-active pigments in the culled tomatoes on overall electricity production. Electrochemical impedance spectroscopy results have elucidated the role of peel and seed on the oxidation behavior of the culled tomatoes., (Copyright © 2016 Elsevier B.V. All rights reserved.)